Four-division world champion Adrien “The Problem’’ Broner and three-division world champion Mikey Garcia square off in a blockbuster matchup in the main event of SHOWTIME CHAMPIONSHIP BOXING®, Saturday, July 29, presented by Premier Boxing Champions at Barclays Center, the home of BROOKLYN BOXING™. Plus, unbeaten former world champion Jermall Charlo returns to face Argentina’s Jorge Sebastian Heiland in a middleweight world title eliminator. Additional undercard action will see former title... see more